1. Field
Embodiments of the present disclosure relate to a motor having an improved structure capable of achieving a reduction in magnetic flux leakage.
2. Description of the Related Art
A motor is a machine to produce rotating force from electrical energy. Such a motor includes a stator and a rotor. The rotor is configured to co-operate with the stator in an electromagnetic manner. The rotor is rotated by a force exerted between a magnetic filed and current flowing through a coil.
Permanent magnet motors, which use permanent magnets to generate an electric field, may be classified into a surface mounted permanent magnet motor, an interior type permanent magnet motor, and a spoke type permanent magnet motor.
The spoke type permanent magnet motor may generate high power with high torque in that it exhibits high magnetic flux concentration. The spoke type permanent magnet motor may also be advantageous in that it may be miniaturized, as compared to other types of motors, for the same output power. The spoke type permanent magnet motor may be applied to drive motors for washing machines or electric vehicles, which require high power with high torque.
Generally, the rotor of the spoke type permanent magnet motor includes permanent magnets arranged about a rotating shaft in a radial manner, and rotor cores each arranged between adjacent ones of the permanent magnets.
In such a spoke type permanent magnet motor, magnetic flux may partially leak toward the rotating shaft through the upper and lower surfaces of the rotor cores. When leakage of magnetic flux increases, the use rate of the permanent magnets may be increased, as compared to other types of motors, for the same motor power. In this case, accordingly, there may be disadvantages in terms of material cost and motor miniaturization.
Furthermore, in the spoke type permanent magnet motor, magnetic flux generated at the stator influences the magnets during rotation of the rotor. As a result, a reduction in the intensity of magnetic flux formed at the magnets, namely, demagnetization, may occur.